In order to simplify the problem of supplies, the Crusader army had split into two groups; the weaker led by Bohemond of Taranto, his nephew Tancred, Robert Curthose, Robert of Flanders, and the Byzantine general Tatikios in the vanguard, and Godfrey of Bouillon, his brother Baldwin of Boulogne, Raymond IV of Toulouse, Stephen II of Blois, and Hugh of Vermandois in the rear.

On the evening of 30 June, after a three-day march, Bohemond's army made camp in a meadow on the north bank of the river Thymbres, near the ruined town of Dorylaeum, believed to be the site of the modern city of Eskişehir.

The Turks were riding into camp, cutting down noncombatants and unarmoured foot soldiers, who were unable to outrun the Turkish horses and were too disoriented and panic-stricken to form lines of battle.

While this formed a battle line and sheltered the more vulnerable men-at-arms and noncombatants, it also gave the Turks free rein to maneuver on the battlefield.

The Turkish mounted archers attacked in their usual style – charging in, shooting their arrows, and quickly retreating before the crusaders could counterattack.

The marshy riverbanks protected the crusaders from mounted charge, as the ground was too soft for horses, and the armoured knights formed a circle protecting the foot soldiers and noncombatants from arrows, but the Turks kept their archers constantly supplied and the sheer number of arrows was taking its toll, reportedly more than 2,000 falling to horse-archers.

Through the day small groups of reinforcements (also from Raymond, and Hugh, as well as Godfrey) arrived, some killed by the Turks, others fighting to reach Bohemond's camp.

The Crusaders had formed a line of battle with Bohemond, Tancred, Robert Curthose, and Stephen on the left wing, Raymond, Robert II of Flanders in the center and Godfrey and Hugh on the right, and they rallied against the Turks, proclaiming "hodie omnes divites si Deo placet effecti eritis" ("today if it pleases God you will all become rich").